ORTHOPTERA. \ 09 



the tip of its wing-covers 29-35 mm. (1.16-1.4 inches), and resembles 

 very closely our common Red-legged Locust, the most abundant of 

 all our species. It can easily be distinguished from this species by 

 the greater length of the wings, which extend about one third of 

 their length beyond the tip of the abdomen, and by the fact that 

 the apex of the last abdominal segment in the males is distinctly 

 notched. 



The permanent home or breedin'g grounds of this species is in 

 the high dry lands on the eastern slope of the Rocky Mountains, 

 extending from the southern limit of the true forests in British 

 America south through Montana, Wyoming, the western part of 

 Dakota, and the Parks of Colorado. There are also regions in which 

 the species exists permanently west of the Rocky Mountains in 

 Idaho and Utah. 



When the food of this insect becomes scarce in its mountain 

 home, it migrates to lower and more fertile regions. Its long wings 

 enable it to travel great distances; and thus the larger part of the 

 region west of the Mississippi River is liable to be invaded by it. 

 Fortunately, the species cannot long survive in the low, moist regions 

 of the valleys. Although the hordes of locusts which reach these 

 sections retain their vigor, and frequently consume every bit of 

 green vegetation, the young, which hatch from the eggs that they 

 lay. perish before reaching maturity. In this way, the invaded 

 region is freed from the pest until it is stocked again by another 

 incursion. There is, however, a large section of country lying 

 immediately east of the great area indicated above as the permanent 

 home of this species, which it frequently invades, and in which it can 

 perpetuate itself for several years, but from which it in time dis- 

 appears. This sub-permanent region, as it has been termed, extends 

 east in British America so as to include nearly one third of Manitoba: 

 and, in the United States, it embraces nearly the whole of Dakota, 

 the half of Nebraska, and the north-east fourth of Colorado. 



The temporary region, or that only periodically visited and from 

 which the species generally disappears within a \< 

 and south so as to include more than half of Minnesota and !< 

 the western tier of counties of Missouri, the whole of Kansas and 

 Indian Territory, and the greater part of Texas. The o>unt- 



ction thus indicated has never been invaded l>> this 

 locust, and t no probabilii : will ever !>< 



The United States Entomological Commission has publi 



8 



